Generally, engines such as gasoline engines, gaseous-fuel engines, and dual-fuel engines, include an ignition system for igniting an air-fuel mixture to produce heat, which may be used to produce mechanical power. Some ignition systems may include a spark plug which may produce a spark to initiate combustion of the air-fuel mixture. Ignition systems typically include a primary coil and a secondary coil coupled to the primary coil. The spark plug is connected across the secondary coil, and a current through the primary coil induces a high voltage across the secondary coil that establishes an are across a spark gap of the spark plug.
In some engines, a monitoring system measures various parameters of the ignition system as the engine operates. An electronic control unit (ECU) (or controller) and/or a machine operator may use information output by the monitoring system to monitor and thereby control engine (more particularly spark plug) operation and/or to determine when sparking is required (e.g., a spark plug cycle needs to be controlled). In some controller systems, an ECU may rely on a fixed primary current and a boost voltage and like parameters to control working of the spark plug, by effectuating change in breakdown time duration. This strategy may have shortcomings such as delivering more than required energy for the spark plug and thereby leading to damage of the spark plug.
U.S. Pat. No. 6,758,199 discloses an ignition system. The ignition system employs a piezoelectric transformer having a drive side and an output side, wherein the output side is in electronic communication with circuit elements that tune output impedance in series with a breakdown gap to optimize power flow from the transformer to the breakdown gap after breakdown. Further, the ignition system includes a timing control circuit in electronic communication with the drive side that meters post-breakdown energy delivered to the breakdown gap by timing the duration of post-breakdown power flow.